Impact analysis of pressure-relief blasting on roadway stability in a deep mining area under high stress

Abstract

In the development of deep underground engineering operations, the surrounding rock is prone to large deformation, rockbursting, and other major engineering disasters. Pressure-relief blasting can improve the stress field in a deep rock mass and prevent the occurrence of roadway collapse. Based on the excavation of the Sandaoshan Mine, ANSYS/LS-DYNA dynamic finite element software is used to simulate the damage and fracture area in the surrounding rock of the roadway under three types of pressure-relief blasting schemes. The strength of the rock mass in the damaged area is reduced, and then the ground stress balance calculation is conducted. The stability of the surrounding rock rock a deep roadway is compared and analysed from aspects of stress and energy and it is verified by theoretical calculation of impact energy factor. The research results show that the non-penetrating fracture zone formed by pressure-relief blasting will increase the stress concentration of the surrounding rock of the roadway, which is more unfavourable to engineering safety. When a reasonable blasting scheme is designed to form a penetrating fracture zone in the surrounding rock of roadway, the concentrated high ground stress in the surrounding rock can be transferred to the deeper part of the rock mass, thereby reducing the elastic strain energy, reducing the risk of a rockburst. Pressure-relief blasting increases the rock mass quality in the failure zone formed by excavation, and reduces the impact energy factor k. When k decreases below the energy threshold, it can prevent rockbursting and ensure the stability of the surrounding rock of the roadway.